A refrigerator is a device which can keep food fresh for a certain period by cooling a freezer compartment or a refrigerator compartment to a specific temperature while repeating a freezing or refrigeration cycle. Generally, a cabinet that forms a storage space and a door that opens or closes a storage space are included in the refrigerator. Stored goods such as food are stored in the storage space, and the user can open the door to keep the stored goods or to take out the kept stored goods.
The most basic and important function of the door of the refrigerator that has this structure is to facilitate a storage or a take-out of the stored goods while making a cool air in the storage space formed inside a cabinet not leak to the outside of the refrigerator. In accordance with the requirements described above, a conventional refrigerator door has been made of an opaque material that is advantageous for cool air maintenance.
However, according to a widespread supply of the refrigerator, in addition to the basic function mentioned above, various requirements for an additional function of the refrigerator are increasing. Recently, a refrigerator that has a door that displays various information related to a refrigerator, for example, information related to a control of the refrigerator or information on the stored goods stored inside the refrigerator is being developed. In such a refrigerator, a display device capable of displaying various information is coupled to the outer surface of the refrigerator door made of an opaque material. The information related to the control of the refrigerator, for example, the information related to the stored goods stored inside the refrigerator or a temperature of the storage compartment of the refrigerator, is displayed through the display device.
Further, a conventional refrigerator is provided with an input device for controlling the refrigerator or inputting a command for searching information by referring to the information displayed through the display device. As the input device provided in the refrigerator, a button type input device that has a physical button or a touch type input device with which a pressure sensing type or a capacitive type touch technology is applied.
On the other hand, in recent years, a refrigerator that a part of a door is formed with a transparent material such as glass is being developed. Through the door described above, the user can identify as to which stored goods are stored inside the storage compartment of the refrigerator without opening the door, so that it is possible to reduce a loss of cool air and to save time for searching the stored goods.
However, it is very difficult to use a conventional button type input device or a touch type input device to which a pressure sensitive or capacitive type touch technology is applied for a refrigerator that has a door formed of such a transparent material. For example, placing a physical button on the transparent panel of the refrigerator door lowers a transparency of the transparent panel and impairs an esthetic sensibility of the refrigerator itself due to a presence of physical buttons.
Further, in the case of pressure sensitive type touch technology, a material that has a predetermined level of elasticity has to be applied to a panel to distinguish a pressure when the user presses the panel. However, the transparent material such as glass is very difficult to obtain the elasticity suitable for the pressure sensitive touch technology.
Further, when the pressure sensitive type or capacitive type touch technology is applied to the entire transparent panel, the price of a refrigerator rises too much due to a high production cost. Further, the pressure sensitive type or capacitive type touch panel has a problem that it has a high failure occurrence rate, and even if a failure occurs in some areas, the entire panel has to be replaced, thereby increasing repair cost.